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Database Articles
Page 514 of 546
Compare DATE string with string from MySQL DATETIME field?
You can compare DATE string with string from DATETIME field with the help of DATE() function in MySQL.The syntax is as follows −select *from yourTableName where DATE(yourColumnName) = ’anyDateString’;To understand the above syntax, let us create a table and set some datetime values in the table. The query to create a table −mysql> create table DateTimeDemo −> ( −> ArrivalTime datetime −> ); Query OK, 0 rows affected (0.61 sec)Let us insert some records in the table with the help of insert command. The following is the query to insert records ...
Read MoreHow to store Query Result in a variable using MySQL?
To store query result in a variable with MySQL, use the SET command. The syntax is as follows −SET @anyVariableName = ( yourQuery);To understand the above concept, let us create a table. The following is the query to create a table −mysql> create table QueryResultDemo −> ( −> Price int −> ); Query OK, 0 rows affected (0.59 sec)Now let us insert some records into the table. The following is the query to insert records −mysql> insert into QueryResultDemo values(100); Query OK, 1 row affected (0.17 sec) mysql> insert into QueryResultDemo values(20); Query OK, 1 row ...
Read MoreHow can I describe all tables in the database through a single statement in MySQL?
You can use INFORMATION_SCHEMA.COLUMNS to describe all tables in database through a single statement. The syntax is as follows.SELECT *FROM INFORMATION_SCHEMA.COLUMNS WHERE TABLE_SCHEMA=’yourDatabaseName’\GHere I am using my database sample with two tables.The table names are as follows −mytableyourtableImplement the above syntax for your database. The query is as follows −mysql> select * FROM information_schema.columns WHERE table_schema = 'sample'\GThe following is the output describing the two tables in our database.*************************** 1. row *************************** TABLE_CATALOG: def TABLE_SCHEMA: sample TABLE_NAME: mytable COLUMN_NAME: id ORDINAL_POSITION: 1 COLUMN_DEFAULT: NULL IS_NULLABLE: YES DATA_TYPE: int CHARACTER_MAXIMUM_LENGTH: NULL CHARACTER_OCTET_LENGTH: NULL NUMERIC_PRECISION: 10 NUMERIC_SCALE: 0 DATETIME_PRECISION: NULL CHARACTER_SET_NAME: NULL ...
Read MoreGroup month and year in MySQL?
You can group month and year with the help of function DATE_FORMAT() in MySQL. The GROUP BY clause is also used.The syntax is as follows −SELECT DATE_FORMAT(yourColumnName, '%m-%Y') from yourTableName GROUP BY MONTH(yourColumnName), YEAR(yourColumnName)DESC;To understand the above concept, let us create a table. The following is the query to create a table −mysql> create table GroupMonthAndYearDemo −> ( −> DueDate datetime −> ); Query OK, 0 rows affected (1.49 sec)Insert records in the table using the following query −mysql> insert into GroupMonthAndYearDemo values(now()); Query OK, 1 row affected (0.11 sec) ...
Read MorePerform MySQL delete under safe mode?
To delete under safe mode, you can use the below query −SET SQL_SAFE_UPDATES = 0;To understand the above query, let us create a table. The following is the query to create a table −mysql> create table SafeDeleteDemo −> ( −> Price int −> ); Query OK, 0 rows affected (0.50 sec)Insert some records in the table with the help of insert command. The query is as follows −mysql> insert into SafeDeleteDemo values(100); Query OK, 1 row affected (0.11 sec) mysql> insert into SafeDeleteDemo values(200); Query OK, 1 row affected (0.19 sec) mysql> insert into SafeDeleteDemo ...
Read MoreHow to count distinct values in MySQL?
To count distinct values, you can use distinct in aggregate function count().The syntax is as follows −select count(distinct yourColumnName) as anyVariableName from yourTableName;To understand the above concept, let us create a table. The following is the query to create a table −mysql> create table DistinctDemo −> ( −> Name varchar(200) −> ); Query OK, 0 rows affected (0.58 sec)For our example, let us insert duplicate records in the table. The query to insert records is as follows −mysql> insert into DistinctDemo values('John'); Query OK, 1 row affected (0.15 sec) mysql> ...
Read MoreUsing group by on two fields and count in MySQL?
To implement GROUP BY on two fields and count, let us create a table. The following is the query to create a table −mysql> create table GroupByTwoFieldsDemo −> ( −> Id int, −> Name varchar(200) −> ); Query OK, 0 rows affected (0.53 sec)Let us insert some records in the table −mysql> insert into GroupByTwoFieldsDemo values(1, 'John'); Query OK, 1 row affected (0.15 sec) mysql> insert into GroupByTwoFieldsDemo values(10, 'Johnson'); Query OK, 1 row affected (0.16 sec) mysql> insert into GroupByTwoFieldsDemo values(9, 'Carol'); Query OK, 1 row affected (0.14 sec) mysql> insert into ...
Read MoreMySQL query to return all records with a datetime older than 1 week
To get dates older than 1 week, you can use the following syntax −select *from yourTableName where yourColumnName < now() - interval 1 week;To understand the above concept, let us create a table. The query to create a table is as follows −mysql> create table DatesOfOneWeek −> ( −> ArrivalTime datetime −> ); Query OK, 0 rows affected (0.87 sec)Insert some records in the table −mysql> insert into DatesOfOneWeek values(date_add(now(), interval 2 week)); Query OK, 1 row affected (0.11 sec) mysql> insert into DatesOfOneWeek values('2018-11-04'); Query OK, 1 row affected ...
Read MoreCreate a table in MySQL that matches another table?
To create a table in MySQL that matches with another table, use CREATE TABLE command with LIKE operator. The syntax is as follows −create table yourNewTableName like yourOldTableName;The above syntax creates structure of the table.If you want all records then use INSERT INTO…...SELECT *FROM command. The syntax is as follows −insert into yourNewTableName select *from yourOldTableName.I have an old table and some data −mysql> create table WholeWordMatchDemo −> ( −> Words varchar(200) −> ); Query OK, 0 rows affected (0.84 sec)First, we will create a table structure. The query is as ...
Read MoreMySQL Select Date Equal to Today and return results for the same date?
To get today’s date, use in-built function CURDATE(). The CURDATE() gives only current date not time. With that, to get the records for the same day, you can try the following syntax −select yourColumnName1, yourColumnName2, ......, yourColumnNameN, DATE_FORMAT(yourDateColumnName, '%Y-%m-%d') from yourTableName WHERE DATE(yourDateColumnName) = CURDATE();To understand the above concept, let us create a table. The query to create a table is as follows. One of these columns will have datetime datatype to display dates −mysql> create table GmailSignIn −> ( −> UserId int, −> UserName varchar(200), −> DateOfSignIn ...
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